Josie and her brother, Sean both have a job after school. For every $5.50 José earns, her brother earns $6.50. On Tuesday, they earned a total of $30.00. How much did Josie earn? How much did her brother earn?

We know that Josie and Sean both work the same number of hours. Since we know their pay rate, we can quickly create a formula with what we know so far:

5.50h + 6.50h = 30.00

Whereas 'h' stands for number of hours worked.
Simplify the equation:

12h = 30.00
Divide:
h = 30.00/12
Simplify;
h = 5.00/2
h = 2.50

They worked for 2.5 hours. Now that we know how many hours they worked, simplify multiply the number of hours by their pay rate:

Josie: 5.50 * 2.5 = $13.75
Sean: 6.50 * 2.5 = $16.25